Single pillar isolator switch

ABSTRACT

In a high voltage isolator switch of the pantograph type, a movable contact of the pivoted tong type cooperates with a counter-contact in the form of a rod suspended vertically from an overhead line. This rod is adapted to be gripped by two substantially horizontally directed elongated contact bars carried by the movable contact. The counter-contact may be provided with longitudinally extending current collecting strips, two on one face and one on the other face. A downwardly-open guiding means secured to the counter-contact guides the contact bars into engagement with the counter-contact.

United States Patent [1 1 Bachler et al.

[451 Aug. 28, 1973 1 SINGLE PILLAR ISOLATOR SWITCH [75] Inventors: Sven Bachler; Sven Erik Akervall;

Sven Wallenstein, all of Ludvika, Sweden [73] Assignee: Allmanna Svenska Elktriska Aktielbolaget, Vasteras, Sweden [22] Filed: Feb. 7, 1972 [21] Appl, No.: 223,924

[30] Foreign Application Priority Data Feb. 12, 1971 Sweden l847/7l [52] U.S. Cl 200/48 V [51] Int. Cl. I-I0lh 31/00 [58] Field of Search 200/48 R, 48 V [56] References Cited UNITED STATES PATENTS 3,530,265 9/1970 Albright 200/48 V FOREIGN PATENTS OR APPLICATIONS 1,356,187 1964 France ZOO/48 V 10/1966 Sweden zoo/4s 4/1962 Germany zoo/4s v Primary Examiner-Herman J. I-lohauser Attorney-Jennings Bailey, Jr.

[ 5 7] ABSTRACT In a high voltage isolator switch of the pantograph type, a movable contact of the pivoted tong type cooperates with a counter-contact in the form of a rod suspended vertically from an overhead line. This rod is adapted to be gripped by two substantially horizontally directed elongated contact bars carried by the movable contact. The counter-contact may be provided with longitudinally extending current collecting strips, two on one face and one on the other face. A downwardly-open guiding means secured to the counter-contact guides the contact bars into engagement with the countercontact.

6 Claims, 7 Drawing Figures PATENTEDM1928 I975 7 55 634 SHEEI 2 0F 2 Fig. 6

SINGLE PILLAR ISOLATOR SWITCH BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an isolator switch having a tong-like contact movable in a vertical plane and supported by an insulator, said contact cooperating with a counter-contact intended to be suspended from an overhead line.

2. The Prior Art In this type of isolator switch, usually called a single pillar isolator switch, the counter-contact normally consists of a horizontal copper rod which is connected to the bus-bar above by means of flexible connections at both ends. In the closed position of the isolator I switch, the movable isolator tong grips said copper rod with a force determined by a torque generated by the driving means of the isolator tong.

One of the most difficult problems with single pillar isolator switches is to control all the different positions which the counter-contact may assume, while still maintaining the desired performance. The countercontact may move both vertically and horizontally because of temperature alterations, wind forces and ice deposits. It must be possible in all these positions for the counter-contact to be caught by the tong contact during a closing action.

With regard to the horizontal displacement perpendicular to the plane of motion of the tong contact, in most constructions the gripping action can be satisfactorily performed with tong arms which have been laterally extended or with a broad counter-contact.

In order to allow for displacement in the plane of motion of the tong, horizontal as well as vertical, the gripping range of the tong must be increased. However, this has the disadvantage that in certain cases the point of contact will be far away from the upper joint of the tong, resulting in a lowering of the contact force.

SUMMARY OF THE INVENTION The object of the present invention is to achieve a solution of the problems mentioned above and associated problems with isolator switches of the type described in single pillar isolator switch. This is achieved by providing a single pillar isolator switch which is characterised in that the counter-contact consists of at least one rodshaped body suspended vertically from the overhead line and arranged in the closed position of the isolator switch to be gripped by two elongated contact bars carried by the tong-shaped contact, said bars being directed substantially horizontally, and thus perpendicularly to the direction of their motion produced by the action of the tong contact. This type of contact arrangement ensures that the contact point will always be at a specified distance from the upper joint of the tong, thus ensuring continued contact pressure at the different levels which the counter-contact may assume.

An extremely stable construction is obtained if the tong contact is constructed of two parallel tong-shaped elements, joined at the top by two cross-pieces which at the same time constitute the contact bars mentioned above.

In order to obtain reliable and specific contact points it is suitable for the rod-shaped counter-contact to be shaped as a rectangular bar on which three current collector strips are attached, two strips being arranged on one broad side of the bar and one strip on the opposite broad side. The contact surfaces of the contact bars of the tong contact which cooperate with the strips should preferably be rounded.

An isolator switch according to thepresent invention can very well be constructed with the contact bars of the tong contact placed below the upper joint of the contact. An important advantage with this arrangement is that, when the isolator switch is open, the contact surfaces of the bars face downwardly so that these surfaces are protected from dirt and snow. Another advantage is that the current path ends before the joint, thus eliminating the difficulty of placing the joint in the middle of the current path.

The contact arrangement according to the invention also makes it possible to guide the tong contact towards the counter-contact in a relatively simple manner by placing a number of gripping arms in a bell-shaped arrangement around the vertical, rod-shaped countercontact, the arms being arranged to cooperate with guiding yokes attached on the upper part of the tong contact. By transferring the guiding function from the tong to the counter-contact to a certain extent, the dimensions of the tong can be made smaller and the decreased weight makes the isolator switch easier to operate. The gripping arms arranged around the countercontact can also be used with advantage as carrier members for a field equalizing ring.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described further with reference to various embodiments shown in the accompanying drawings. FIG. 1 shows schematically in perspective a pole of a first embodiment of a single pillar isolator switch according to the invention. FIG. 2 shows a contact means for such an isolator switch, seen from above. FIGS. 3 and 4 show two side views perpendicular to each other of a second embodiment of a single pillar isolator switch according to the invention. FIGS. 5, 6 and 7 show from the side and from above an isolator switch of the type shown in FIGS. 3-4 provided with guiding means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The isolator according to FIG. 1 comprises a movable contact in the form of a double tong consisting of two parallel, tong-shaped elements 1 and 2 which, above the upper joints 3 and 4, are connected by means of two cross-pieces 5 and 6, simultaneously acting as contact bars. These contact bars cooperate with a counter-contact 7 suspended from an overhead line which forms a bus-bar in a switchgear station. The counter-contact 7 consists of a vertically suspended rod-shaped body. The gripping contact 1,2 is fitted on a driving means 10 supported by a support insulator 9, a terminal bar, not'shown, being arranged on this driving means for an out-going conductor. The isolator is operated by means of a pivotable operating insulator 11. FIG. I shows the isolator switch during an operating movement where the contact bars 5,6 are on their way to the closed position, in which the contact bars clamp the counter-contact 7 hanging down between them. With such an arrangement of the contact device the contact points will always be located at a specific distance from the joints 3 and 4 and the contact force will therefore be independent of the level of the counter-contact 7.

The rod-shaped counter-contact 7 consists of a bar or plate on which three longitudinal copper strips 12 having, for example, semi-circular cross-section are attached. Two of the strips are arranged on one side of the bar and one of the other side. Since the bar 7 is relatively long and attached to the overhead line 8 so that it can swing easily, it can adjust itself so that all three strips receive some of the contact force (although not equally distributed) when the two contact bars and 6 on the tong contact clamp around the counter-contact 7. The contact 7 can easily be increased to double capacity if two bars are placed beside each other as shown in FIG. 2. The bars in the counter-contact 7 are then turned so that each of the contact bars 5 and 6 makes contact with three current collector strips 12. As shown in FIG. 2, all the contact points partake of the contact force even if the contact bars 5 and 6 become curved because of the load from the arms of the tong contact 1,2, symbolised by arrows.

in the isolator switch shown in FIGS. 3 and 4 the contact bars 5 and 6 are below the joints 3 and 4. As can be seen from FIG. 3, where the isolator switch is shown both in closed and open position (with solid and broken lines, respectively), this means that the contact surfaces on the contact bars 5 and 6 face downwardly in the open position, thus protecting the surfaces from dirt and snow.

The isolator switch shown in FIGS. 5 7 is provided with a substantially square field equalizing ring 13 which is attached by four support arms 14 to the upper part of the counter-contact 7. The support arms 14 are designed so that, together with two guiding yokes 15 1 and 16 attached to the upper part of the tong elements 1,2, they guide the counter-contact 7 towards the contact bars 5 and 6.

The tong contact 1,2 need not necessarily be in the form ofa double tong. The main thing is that the horizontal contact bars 5 and 6 are sufficiently long.

We claim:

1. isolator switch comprising a counter-contact in the form of an elongated body adapted to be suspended vertically from an overhead line, an insulating base, a pair of elongated contact bars, and tong-type mounting means carrying said bars above the base on opposite sides of the countencontact for movement towards and from each other to clamp the counter-contact therebetween, said bars extending in directions substantially perpendicular to such movement and being positioned below the upper joint of said mounting means.

2. isolator switch as claimed in claim 1, in which said contact bars extend horizontally at substantially the same height above said base.

3. isolator switch as claimed in claim 1, in which said mounting means includes two parallel tong-type mountings, the contact bars extending between the mountings.

4. isolator switch as claimed in claim 1, in which said counter-contact comprises a plate-like body having three longitudinally extending contact strips, one on one side and two on the opposite side.

5. isolator switch as claimed in claim 4 having two counter-contacts engageable between the contact bars.

6. isolator switch as claimed in claim 1, having a field equalizing ring and support members connected to said counter-contact remote from its lower end extending outwardly and downwardly therefrom and supporting said ring, said tong-type mounting means including guiding members adjacent said contact bars and engageable during upward movement with the support members to guide the contact bars into position to clamp the counter-contact between them 

1. Isolator switch comprising a counter-contact in the form of an elongated body adapted to be suspended vertically from an overhead line, an insulating base, a pair of elongated contact bars, and tong-type mounting means carrying said bars above the base on opposite sides of the counter-contact for movement towards and from each other to clamp the counter-contact therebetween, said bars extending in directions substantially perpendicular to such movement and being positioned below the upper joint of said mounting means.
 2. Isolator switch as claimed in claim 1, in which said contact bars extend horizontally at substantially the same height above said base.
 3. Isolator switch as claimed in claim 1, in which said mounting means includes two parallel tong-type mountings, the contact bars extending between the mountings.
 4. Isolator switch as claimed in claim 1, in which said counter-contact comprises a plate-like body having three longitudinally extending contact strips, one on one side and two on the opposite side.
 5. Isolator switch as claimed in claim 4 having two counter-contacts engageable between the contact bars.
 6. Isolator switch as claimed in claim 1, having a field equalizing ring and support members connected to said counter-contact remote from its lower end extending outwardly and downwardly therefrom and supporting said ring, said tong-type mounting means including guiding members adjacent said contact bars and engageable during upward movement with the support members to guide the contact bars into position to clamp the counter-contact between them. 